1. Field of the Invention
The present invention relates to a control technique of carrying out a predetermined process in response to an input of a trigger signal.
2. Description of the Background Art
Conventionally, with respect to a detection device for detecting invasion into a monitoring area, a device which has, for example, an invasion detection sensor, a monitor camera and a speaker, and allows the monitor camera to capture and record images in the vicinity of the invasion position, as well as allowing the speaker to give a warning voice or the like, in response to a trigger signal generated by the detection sensor upon detection of any intruding object has been proposed (e.g., Japanese Patent Application Laid-Open No. 2003-44965). In the detection device of this type, when the invasion detection sensor has detected any intruding object, it is unconditionally determined that there is any abnormality, and predetermined operations (image capturing and recording operations, warning operations and the like) are carried out.
However, in the conventional device, when detected by the detection sensor, any object is determined as an abnormal object; therefore, for example, when a detection sensor is attached to a common entrance, door or the like, there is a problem in that a warning voice is given even to a normal passenger who is not a suspicious intruder.